The fputs function writes a string to the file.
int fputs ( const char* Str, /* String */ FIL* FileObject /* File object */ );
When the function succeeded, number of characters written (not minus value) is returned. When the function failed due to disk full or any error, an EOF will be returned.
The fputs() is a wrapper function of fputc(). This function is available when read-write configuration and _USE_STRFUNC is 1 or 2. When it is set 2, a '\n' is extended to "\r\n".